From 9f0fc191371843c4fc000a226b0a26b6c059aacd Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sat, 18 May 2024 19:40:19 +0200 Subject: Merging upstream version 6.7.7. Signed-off-by: Daniel Baumann --- scripts/mod/Makefile | 4 +- scripts/mod/devicetable-offsets.c | 7 ++ scripts/mod/file2alias.c | 17 ++++ scripts/mod/modpost.c | 204 ++++++++++---------------------------- scripts/mod/modpost.h | 50 +++++++--- scripts/mod/sumversion.c | 7 +- scripts/mod/symsearch.c | 199 +++++++++++++++++++++++++++++++++++++ 7 files changed, 319 insertions(+), 169 deletions(-) create mode 100644 scripts/mod/symsearch.c (limited to 'scripts/mod') diff --git a/scripts/mod/Makefile b/scripts/mod/Makefile index c9e38ad937..3c54125eb3 100644 --- a/scripts/mod/Makefile +++ b/scripts/mod/Makefile @@ -5,7 +5,7 @@ CFLAGS_REMOVE_empty.o += $(CC_FLAGS_LTO) hostprogs-always-y += modpost mk_elfconfig always-y += empty.o -modpost-objs := modpost.o file2alias.o sumversion.o +modpost-objs := modpost.o file2alias.o sumversion.o symsearch.o devicetable-offsets-file := devicetable-offsets.h @@ -16,7 +16,7 @@ targets += $(devicetable-offsets-file) devicetable-offsets.s # dependencies on generated files need to be listed explicitly -$(obj)/modpost.o $(obj)/file2alias.o $(obj)/sumversion.o: $(obj)/elfconfig.h +$(obj)/modpost.o $(obj)/file2alias.o $(obj)/sumversion.o $(obj)/symsearch.o: $(obj)/elfconfig.h $(obj)/file2alias.o: $(obj)/$(devicetable-offsets-file) quiet_cmd_elfconfig = MKELF $@ diff --git a/scripts/mod/devicetable-offsets.c b/scripts/mod/devicetable-offsets.c index abe65f8968..e91a3c3814 100644 --- a/scripts/mod/devicetable-offsets.c +++ b/scripts/mod/devicetable-offsets.c @@ -265,7 +265,14 @@ int main(void) DEVID(cdx_device_id); DEVID_FIELD(cdx_device_id, vendor); DEVID_FIELD(cdx_device_id, device); + DEVID_FIELD(cdx_device_id, subvendor); + DEVID_FIELD(cdx_device_id, subdevice); + DEVID_FIELD(cdx_device_id, class); + DEVID_FIELD(cdx_device_id, class_mask); DEVID_FIELD(cdx_device_id, override_only); + DEVID(vchiq_device_id); + DEVID_FIELD(vchiq_device_id, name); + return 0; } diff --git a/scripts/mod/file2alias.c b/scripts/mod/file2alias.c index 6583b36dbe..4829680a0a 100644 --- a/scripts/mod/file2alias.c +++ b/scripts/mod/file2alias.c @@ -1458,6 +1458,10 @@ static int do_cdx_entry(const char *filename, void *symval, { DEF_FIELD(symval, cdx_device_id, vendor); DEF_FIELD(symval, cdx_device_id, device); + DEF_FIELD(symval, cdx_device_id, subvendor); + DEF_FIELD(symval, cdx_device_id, subdevice); + DEF_FIELD(symval, cdx_device_id, class); + DEF_FIELD(symval, cdx_device_id, class_mask); DEF_FIELD(symval, cdx_device_id, override_only); switch (override_only) { @@ -1475,6 +1479,18 @@ static int do_cdx_entry(const char *filename, void *symval, ADD(alias, "v", vendor != CDX_ANY_ID, vendor); ADD(alias, "d", device != CDX_ANY_ID, device); + ADD(alias, "sv", subvendor != CDX_ANY_ID, subvendor); + ADD(alias, "sd", subdevice != CDX_ANY_ID, subdevice); + ADD(alias, "c", class_mask == 0xFFFFFF, class); + + return 1; +} + +static int do_vchiq_entry(const char *filename, void *symval, char *alias) +{ + DEF_FIELD_ADDR(symval, vchiq_device_id, name); + sprintf(alias, "vchiq:%s", *name); + return 1; } @@ -1558,6 +1574,7 @@ static const struct devtable devtable[] = { {"dfl", SIZE_dfl_device_id, do_dfl_entry}, {"ishtp", SIZE_ishtp_device_id, do_ishtp_entry}, {"cdx", SIZE_cdx_device_id, do_cdx_entry}, + {"vchiq", SIZE_vchiq_device_id, do_vchiq_entry}, }; /* Create MODULE_ALIAS() statements. diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index ac4ef3e206..f7c4d3fe43 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -22,7 +22,6 @@ #include #include "modpost.h" #include "../../include/linux/license.h" -#include "../../include/linux/module_symbol.h" static bool module_enabled; /* Are we using CONFIG_MODVERSIONS? */ @@ -577,11 +576,14 @@ static int parse_elf(struct elf_info *info, const char *filename) *p = TO_NATIVE(*p); } + symsearch_init(info); + return 1; } static void parse_elf_finish(struct elf_info *info) { + symsearch_finish(info); release_file(info->hdr, info->size); } @@ -792,47 +794,33 @@ static void check_section(const char *modname, struct elf_info *elf, #define ALL_INIT_DATA_SECTIONS \ ".init.setup", ".init.rodata", ".meminit.rodata", \ ".init.data", ".meminit.data" -#define ALL_EXIT_DATA_SECTIONS \ - ".exit.data", ".memexit.data" - -#define ALL_INIT_TEXT_SECTIONS \ - ".init.text", ".meminit.text" -#define ALL_EXIT_TEXT_SECTIONS \ - ".exit.text", ".memexit.text" #define ALL_PCI_INIT_SECTIONS \ ".pci_fixup_early", ".pci_fixup_header", ".pci_fixup_final", \ ".pci_fixup_enable", ".pci_fixup_resume", \ ".pci_fixup_resume_early", ".pci_fixup_suspend" -#define ALL_XXXINIT_SECTIONS MEM_INIT_SECTIONS -#define ALL_XXXEXIT_SECTIONS MEM_EXIT_SECTIONS +#define ALL_XXXINIT_SECTIONS ".meminit.*" #define ALL_INIT_SECTIONS INIT_SECTIONS, ALL_XXXINIT_SECTIONS -#define ALL_EXIT_SECTIONS EXIT_SECTIONS, ALL_XXXEXIT_SECTIONS +#define ALL_EXIT_SECTIONS ".exit.*" #define DATA_SECTIONS ".data", ".data.rel" #define TEXT_SECTIONS ".text", ".text.*", ".sched.text", \ - ".kprobes.text", ".cpuidle.text", ".noinstr.text" + ".kprobes.text", ".cpuidle.text", ".noinstr.text", \ + ".ltext", ".ltext.*" #define OTHER_TEXT_SECTIONS ".ref.text", ".head.text", ".spinlock.text", \ ".fixup", ".entry.text", ".exception.text", \ ".coldtext", ".softirqentry.text" #define INIT_SECTIONS ".init.*" -#define MEM_INIT_SECTIONS ".meminit.*" -#define EXIT_SECTIONS ".exit.*" -#define MEM_EXIT_SECTIONS ".memexit.*" - -#define ALL_TEXT_SECTIONS ALL_INIT_TEXT_SECTIONS, ALL_EXIT_TEXT_SECTIONS, \ +#define ALL_TEXT_SECTIONS ".init.text", ".meminit.text", ".exit.text", \ TEXT_SECTIONS, OTHER_TEXT_SECTIONS enum mismatch { - TEXT_TO_ANY_INIT, - DATA_TO_ANY_INIT, - TEXTDATA_TO_ANY_EXIT, + TEXTDATA_TO_ANY_INIT_EXIT, XXXINIT_TO_SOME_INIT, - XXXEXIT_TO_SOME_EXIT, ANY_INIT_TO_ANY_EXIT, ANY_EXIT_TO_ANY_INIT, EXTABLE_TO_NON_TEXT, @@ -862,20 +850,10 @@ static const struct sectioncheck sectioncheck[] = { /* Do not reference init/exit code/data from * normal code and data */ -{ - .fromsec = { TEXT_SECTIONS, NULL }, - .bad_tosec = { ALL_INIT_SECTIONS, NULL }, - .mismatch = TEXT_TO_ANY_INIT, -}, -{ - .fromsec = { DATA_SECTIONS, NULL }, - .bad_tosec = { ALL_XXXINIT_SECTIONS, INIT_SECTIONS, NULL }, - .mismatch = DATA_TO_ANY_INIT, -}, { .fromsec = { TEXT_SECTIONS, DATA_SECTIONS, NULL }, - .bad_tosec = { ALL_EXIT_SECTIONS, NULL }, - .mismatch = TEXTDATA_TO_ANY_EXIT, + .bad_tosec = { ALL_INIT_SECTIONS, ALL_EXIT_SECTIONS, NULL }, + .mismatch = TEXTDATA_TO_ANY_INIT_EXIT, }, /* Do not reference init code/data from meminit code/data */ { @@ -883,12 +861,6 @@ static const struct sectioncheck sectioncheck[] = { .bad_tosec = { INIT_SECTIONS, NULL }, .mismatch = XXXINIT_TO_SOME_INIT, }, -/* Do not reference exit code/data from memexit code/data */ -{ - .fromsec = { ALL_XXXEXIT_SECTIONS, NULL }, - .bad_tosec = { EXIT_SECTIONS, NULL }, - .mismatch = XXXEXIT_TO_SOME_EXIT, -}, /* Do not use exit code/data from init code */ { .fromsec = { ALL_INIT_SECTIONS, NULL }, @@ -1006,19 +978,7 @@ static int secref_whitelist(const char *fromsec, const char *fromsym, /* symbols in data sections that may refer to any init/exit sections */ if (match(fromsec, PATTERNS(DATA_SECTIONS)) && match(tosec, PATTERNS(ALL_INIT_SECTIONS, ALL_EXIT_SECTIONS)) && - match(fromsym, PATTERNS("*_template", // scsi uses *_template a lot - "*_timer", // arm uses ops structures named _timer a lot - "*_sht", // scsi also used *_sht to some extent - "*_ops", - "*_probe", - "*_probe_one", - "*_console"))) - return 0; - - /* symbols in data sections that may refer to meminit sections */ - if (match(fromsec, PATTERNS(DATA_SECTIONS)) && - match(tosec, PATTERNS(ALL_XXXINIT_SECTIONS, ALL_XXXEXIT_SECTIONS)) && - match(fromsym, PATTERNS("*driver"))) + match(fromsym, PATTERNS("*_ops", "*_probe", "*_console"))) return 0; /* @@ -1028,7 +988,7 @@ static int secref_whitelist(const char *fromsec, const char *fromsym, */ if (!extra_warn && match(fromsec, PATTERNS(DATA_SECTIONS)) && - match(tosec, PATTERNS(EXIT_SECTIONS)) && + match(tosec, PATTERNS(ALL_EXIT_SECTIONS)) && match(fromsym, PATTERNS("*driver"))) return 0; @@ -1050,71 +1010,10 @@ static int secref_whitelist(const char *fromsec, const char *fromsym, return 1; } -/* - * If there's no name there, ignore it; likewise, ignore it if it's - * one of the magic symbols emitted used by current tools. - * - * Otherwise if find_symbols_between() returns those symbols, they'll - * fail the whitelist tests and cause lots of false alarms ... fixable - * only by merging __exit and __init sections into __text, bloating - * the kernel (which is especially evil on embedded platforms). - */ -static inline int is_valid_name(struct elf_info *elf, Elf_Sym *sym) -{ - const char *name = elf->strtab + sym->st_name; - - if (!name || !strlen(name)) - return 0; - return !is_mapping_symbol(name); -} - -/* Look up the nearest symbol based on the section and the address */ -static Elf_Sym *find_nearest_sym(struct elf_info *elf, Elf_Addr addr, - unsigned int secndx, bool allow_negative, - Elf_Addr min_distance) -{ - Elf_Sym *sym; - Elf_Sym *near = NULL; - Elf_Addr sym_addr, distance; - bool is_arm = (elf->hdr->e_machine == EM_ARM); - - for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) { - if (get_secindex(elf, sym) != secndx) - continue; - if (!is_valid_name(elf, sym)) - continue; - - sym_addr = sym->st_value; - - /* - * For ARM Thumb instruction, the bit 0 of st_value is set - * if the symbol is STT_FUNC type. Mask it to get the address. - */ - if (is_arm && ELF_ST_TYPE(sym->st_info) == STT_FUNC) - sym_addr &= ~1; - - if (addr >= sym_addr) - distance = addr - sym_addr; - else if (allow_negative) - distance = sym_addr - addr; - else - continue; - - if (distance <= min_distance) { - min_distance = distance; - near = sym; - } - - if (min_distance == 0) - break; - } - return near; -} - static Elf_Sym *find_fromsym(struct elf_info *elf, Elf_Addr addr, unsigned int secndx) { - return find_nearest_sym(elf, addr, secndx, false, ~0); + return symsearch_find_nearest(elf, addr, secndx, false, ~0); } static Elf_Sym *find_tosym(struct elf_info *elf, Elf_Addr addr, Elf_Sym *sym) @@ -1127,7 +1026,8 @@ static Elf_Sym *find_tosym(struct elf_info *elf, Elf_Addr addr, Elf_Sym *sym) * Strive to find a better symbol name, but the resulting name may not * match the symbol referenced in the original code. */ - return find_nearest_sym(elf, addr, get_secindex(elf, sym), true, 20); + return symsearch_find_nearest(elf, addr, get_secindex(elf, sym), + true, 20); } static bool is_executable_section(struct elf_info *elf, unsigned int secndx) @@ -1248,10 +1148,10 @@ static void check_export_symbol(struct module *mod, struct elf_info *elf, ELF_ST_TYPE(sym->st_info) == STT_LOPROC) s->is_func = true; - if (match(secname, PATTERNS(INIT_SECTIONS))) + if (match(secname, PATTERNS(ALL_INIT_SECTIONS))) warn("%s: %s: EXPORT_SYMBOL used for init symbol. Remove __init or EXPORT_SYMBOL.\n", mod->name, name); - else if (match(secname, PATTERNS(EXIT_SECTIONS))) + else if (match(secname, PATTERNS(ALL_EXIT_SECTIONS))) warn("%s: %s: EXPORT_SYMBOL used for exit symbol. Remove __exit or EXPORT_SYMBOL.\n", mod->name, name); } @@ -1468,32 +1368,20 @@ static void get_rel_type_and_sym(struct elf_info *elf, uint64_t r_info, return; } - if (is_64bit) { - Elf64_Xword r_info64 = r_info; - - r_info = TO_NATIVE(r_info64); - } else { - Elf32_Word r_info32 = r_info; - - r_info = TO_NATIVE(r_info32); - } + if (is_64bit) + r_info = TO_NATIVE((Elf64_Xword)r_info); + else + r_info = TO_NATIVE((Elf32_Word)r_info); *r_type = ELF_R_TYPE(r_info); *r_sym = ELF_R_SYM(r_info); } static void section_rela(struct module *mod, struct elf_info *elf, - Elf_Shdr *sechdr) + unsigned int fsecndx, const char *fromsec, + const Elf_Rela *start, const Elf_Rela *stop) { - Elf_Rela *rela; - unsigned int fsecndx = sechdr->sh_info; - const char *fromsec = sec_name(elf, fsecndx); - Elf_Rela *start = (void *)elf->hdr + sechdr->sh_offset; - Elf_Rela *stop = (void *)start + sechdr->sh_size; - - /* if from section (name) is know good then skip it */ - if (match(fromsec, section_white_list)) - return; + const Elf_Rela *rela; for (rela = start; rela < stop; rela++) { Elf_Sym *tsym; @@ -1525,17 +1413,10 @@ static void section_rela(struct module *mod, struct elf_info *elf, } static void section_rel(struct module *mod, struct elf_info *elf, - Elf_Shdr *sechdr) + unsigned int fsecndx, const char *fromsec, + const Elf_Rel *start, const Elf_Rel *stop) { - Elf_Rel *rel; - unsigned int fsecndx = sechdr->sh_info; - const char *fromsec = sec_name(elf, fsecndx); - Elf_Rel *start = (void *)elf->hdr + sechdr->sh_offset; - Elf_Rel *stop = (void *)start + sechdr->sh_size; - - /* if from section (name) is know good then skip it */ - if (match(fromsec, section_white_list)) - return; + const Elf_Rel *rel; for (rel = start; rel < stop; rel++) { Elf_Sym *tsym; @@ -1583,16 +1464,33 @@ static void section_rel(struct module *mod, struct elf_info *elf, static void check_sec_ref(struct module *mod, struct elf_info *elf) { int i; - Elf_Shdr *sechdrs = elf->sechdrs; /* Walk through all sections */ for (i = 0; i < elf->num_sections; i++) { - check_section(mod->name, elf, &elf->sechdrs[i]); + Elf_Shdr *sechdr = &elf->sechdrs[i]; + + check_section(mod->name, elf, sechdr); /* We want to process only relocation sections and not .init */ - if (sechdrs[i].sh_type == SHT_RELA) - section_rela(mod, elf, &elf->sechdrs[i]); - else if (sechdrs[i].sh_type == SHT_REL) - section_rel(mod, elf, &elf->sechdrs[i]); + if (sechdr->sh_type == SHT_REL || sechdr->sh_type == SHT_RELA) { + /* section to which the relocation applies */ + unsigned int secndx = sechdr->sh_info; + const char *secname = sec_name(elf, secndx); + const void *start, *stop; + + /* If the section is known good, skip it */ + if (match(secname, section_white_list)) + continue; + + start = sym_get_data_by_offset(elf, i, 0); + stop = start + sechdr->sh_size; + + if (sechdr->sh_type == SHT_RELA) + section_rela(mod, elf, secndx, secname, + start, stop); + else + section_rel(mod, elf, secndx, secname, + start, stop); + } } } diff --git a/scripts/mod/modpost.h b/scripts/mod/modpost.h index 5f94c2c9f2..69baf014da 100644 --- a/scripts/mod/modpost.h +++ b/scripts/mod/modpost.h @@ -1,4 +1,5 @@ /* SPDX-License-Identifier: GPL-2.0 */ +#include #include #include #include @@ -10,6 +11,7 @@ #include #include #include +#include "../../include/linux/module_symbol.h" #include "list.h" #include "elfconfig.h" @@ -50,21 +52,19 @@ #define ELF_R_TYPE ELF64_R_TYPE #endif -#if KERNEL_ELFDATA != HOST_ELFDATA +#define bswap(x) \ +({ \ + _Static_assert(sizeof(x) == 1 || sizeof(x) == 2 || \ + sizeof(x) == 4 || sizeof(x) == 8, "bug"); \ + (typeof(x))(sizeof(x) == 2 ? bswap_16(x) : \ + sizeof(x) == 4 ? bswap_32(x) : \ + sizeof(x) == 8 ? bswap_64(x) : \ + x); \ +}) -static inline void __endian(const void *src, void *dest, unsigned int size) -{ - unsigned int i; - for (i = 0; i < size; i++) - ((unsigned char*)dest)[i] = ((unsigned char*)src)[size - i-1]; -} +#if KERNEL_ELFDATA != HOST_ELFDATA -#define TO_NATIVE(x) \ -({ \ - typeof(x) __x; \ - __endian(&(x), &(__x), sizeof(__x)); \ - __x; \ -}) +#define TO_NATIVE(x) (bswap(x)) #else /* endianness matches */ @@ -128,6 +128,8 @@ struct elf_info { * take shndx from symtab_shndx_start[N] instead */ Elf32_Word *symtab_shndx_start; Elf32_Word *symtab_shndx_stop; + + struct symsearch *symsearch; }; /* Accessor for sym->st_shndx, hides ugliness of "64k sections" */ @@ -154,6 +156,28 @@ static inline unsigned int get_secindex(const struct elf_info *info, return index; } +/* + * If there's no name there, ignore it; likewise, ignore it if it's + * one of the magic symbols emitted used by current tools. + * + * Internal symbols created by tools should be ignored by modpost. + */ +static inline bool is_valid_name(struct elf_info *elf, Elf_Sym *sym) +{ + const char *name = elf->strtab + sym->st_name; + + if (!name || !strlen(name)) + return false; + return !is_mapping_symbol(name); +} + +/* symsearch.c */ +void symsearch_init(struct elf_info *elf); +void symsearch_finish(struct elf_info *elf); +Elf_Sym *symsearch_find_nearest(struct elf_info *elf, Elf_Addr addr, + unsigned int secndx, bool allow_negative, + Elf_Addr min_distance); + /* file2alias.c */ void handle_moddevtable(struct module *mod, struct elf_info *info, Elf_Sym *sym, const char *symname); diff --git a/scripts/mod/sumversion.c b/scripts/mod/sumversion.c index 31066bfdba..dc48785022 100644 --- a/scripts/mod/sumversion.c +++ b/scripts/mod/sumversion.c @@ -326,7 +326,12 @@ static int parse_source_files(const char *objfile, struct md4_ctx *md) /* Sum all files in the same dir or subdirs. */ while ((line = get_line(&pos))) { - char* p = line; + char* p; + + /* trim the leading spaces away */ + while (isspace(*line)) + line++; + p = line; if (strncmp(line, "source_", sizeof("source_")-1) == 0) { p = strrchr(line, ' '); diff --git a/scripts/mod/symsearch.c b/scripts/mod/symsearch.c new file mode 100644 index 0000000000..aa4ed51f99 --- /dev/null +++ b/scripts/mod/symsearch.c @@ -0,0 +1,199 @@ +// SPDX-License-Identifier: GPL-2.0 + +/* + * Helper functions for finding the symbol in an ELF which is "nearest" + * to a given address. + */ + +#include "modpost.h" + +struct syminfo { + unsigned int symbol_index; + unsigned int section_index; + Elf_Addr addr; +}; + +/* + * Container used to hold an entire binary search table. + * Entries in table are ascending, sorted first by section_index, + * then by addr, and last by symbol_index. The sorting by + * symbol_index is used to ensure predictable behavior when + * multiple symbols are present with the same address; all + * symbols past the first are effectively ignored, by eliding + * them in symsearch_fixup(). + */ +struct symsearch { + unsigned int table_size; + struct syminfo table[]; +}; + +static int syminfo_compare(const void *s1, const void *s2) +{ + const struct syminfo *sym1 = s1; + const struct syminfo *sym2 = s2; + + if (sym1->section_index > sym2->section_index) + return 1; + if (sym1->section_index < sym2->section_index) + return -1; + if (sym1->addr > sym2->addr) + return 1; + if (sym1->addr < sym2->addr) + return -1; + if (sym1->symbol_index > sym2->symbol_index) + return 1; + if (sym1->symbol_index < sym2->symbol_index) + return -1; + return 0; +} + +static unsigned int symbol_count(struct elf_info *elf) +{ + unsigned int result = 0; + + for (Elf_Sym *sym = elf->symtab_start; sym < elf->symtab_stop; sym++) { + if (is_valid_name(elf, sym)) + result++; + } + return result; +} + +/* + * Populate the search array that we just allocated. + * Be slightly paranoid here. The ELF file is mmap'd and could + * conceivably change between symbol_count() and symsearch_populate(). + * If we notice any difference, bail out rather than potentially + * propagating errors or crashing. + */ +static void symsearch_populate(struct elf_info *elf, + struct syminfo *table, + unsigned int table_size) +{ + bool is_arm = (elf->hdr->e_machine == EM_ARM); + + for (Elf_Sym *sym = elf->symtab_start; sym < elf->symtab_stop; sym++) { + if (is_valid_name(elf, sym)) { + if (table_size-- == 0) + fatal("%s: size mismatch\n", __func__); + table->symbol_index = sym - elf->symtab_start; + table->section_index = get_secindex(elf, sym); + table->addr = sym->st_value; + + /* + * For ARM Thumb instruction, the bit 0 of st_value is + * set if the symbol is STT_FUNC type. Mask it to get + * the address. + */ + if (is_arm && ELF_ST_TYPE(sym->st_info) == STT_FUNC) + table->addr &= ~1; + + table++; + } + } + + if (table_size != 0) + fatal("%s: size mismatch\n", __func__); +} + +/* + * Do any fixups on the table after sorting. + * For now, this just finds adjacent entries which have + * the same section_index and addr, and it propagates + * the first symbol_index over the subsequent entries, + * so that only one symbol_index is seen for any given + * section_index and addr. This ensures that whether + * we're looking at an address from "above" or "below" + * that we see the same symbol_index. + * This does leave some duplicate entries in the table; + * in practice, these are a small fraction of the + * total number of entries, and they are harmless to + * the binary search algorithm other than a few occasional + * unnecessary comparisons. + */ +static void symsearch_fixup(struct syminfo *table, unsigned int table_size) +{ + /* Don't look at index 0, it will never change. */ + for (unsigned int i = 1; i < table_size; i++) { + if (table[i].addr == table[i - 1].addr && + table[i].section_index == table[i - 1].section_index) { + table[i].symbol_index = table[i - 1].symbol_index; + } + } +} + +void symsearch_init(struct elf_info *elf) +{ + unsigned int table_size = symbol_count(elf); + + elf->symsearch = NOFAIL(malloc(sizeof(struct symsearch) + + sizeof(struct syminfo) * table_size)); + elf->symsearch->table_size = table_size; + + symsearch_populate(elf, elf->symsearch->table, table_size); + qsort(elf->symsearch->table, table_size, + sizeof(struct syminfo), syminfo_compare); + + symsearch_fixup(elf->symsearch->table, table_size); +} + +void symsearch_finish(struct elf_info *elf) +{ + free(elf->symsearch); + elf->symsearch = NULL; +} + +/* + * Find the syminfo which is in secndx and "nearest" to addr. + * allow_negative: allow returning a symbol whose address is > addr. + * min_distance: ignore symbols which are further away than this. + * + * Returns a pointer into the symbol table for success. + * Returns NULL if no legal symbol is found within the requested range. + */ +Elf_Sym *symsearch_find_nearest(struct elf_info *elf, Elf_Addr addr, + unsigned int secndx, bool allow_negative, + Elf_Addr min_distance) +{ + unsigned int hi = elf->symsearch->table_size; + unsigned int lo = 0; + struct syminfo *table = elf->symsearch->table; + struct syminfo target; + + target.addr = addr; + target.section_index = secndx; + target.symbol_index = ~0; /* compares greater than any actual index */ + while (hi > lo) { + unsigned int mid = lo + (hi - lo) / 2; /* Avoids overflow */ + + if (syminfo_compare(&table[mid], &target) > 0) + hi = mid; + else + lo = mid + 1; + } + + /* + * table[hi], if it exists, is the first entry in the array which + * lies beyond target. table[hi - 1], if it exists, is the last + * entry in the array which comes before target, including the + * case where it perfectly matches the section and the address. + * + * Note -- if the address we're looking up falls perfectly + * in the middle of two symbols, this is written to always + * prefer the symbol with the lower address. + */ + Elf_Sym *result = NULL; + + if (allow_negative && + hi < elf->symsearch->table_size && + table[hi].section_index == secndx && + table[hi].addr - addr <= min_distance) { + min_distance = table[hi].addr - addr; + result = &elf->symtab_start[table[hi].symbol_index]; + } + if (hi > 0 && + table[hi - 1].section_index == secndx && + addr - table[hi - 1].addr <= min_distance) { + result = &elf->symtab_start[table[hi - 1].symbol_index]; + } + return result; +} -- cgit v1.2.3